Control device for display apparatus

ABSTRACT

A control device for a display apparatus having storage means for successively storing information to be displayed. The storage means consists of a magnetostrictive delay line, and, pieces of information bearing the head marks of the display apparatus are divided into individual display lines. Means, including forward and backward shifting keys, are provided for extinguishing the pieces of information presented on the terminal display apparatus which represent the first or last display lines and successively shifting the following display lines to a blank space, and, displaying the display line preceding or following the already indicated display line on the last or first display line thus rendered blank.

Elite States Matsushita et a1,

atent 541 CONTROL DEVICE FOR DISPLAY APPARATUS [72] Inventors: Shigenori Matsushita, Yokohama; Fumitaka Sato, Kawasaki; Hisao Chujo, Yokohama, all of Japan [73] Assignee: Tokyo Shibaura Electric Co., Ltd.,

Kawasaki-shi, Japan [22] Filed: July 1, 1971 [21] Appl. No.: 158,872

Related US. Application Data [63] Continuation-in-part of Ser. No. 724,439, April 26, 1968, abandoned.

EELAY CIRCUIT Aug. 29, 1972 3,555,520 1/1971 Helbig et a1 ..340/324 A 3,593,310 7/1971 Kievit ..340/324 A X 3,611,348 10/1971 Rogers ..340/324 A 3,614,766 10/1971 Kievit ..340/324 A Primary Examiner-David L. Trafton Attorney-George B. Oujevolk ABSTRACT A control device for a display apparatus having storage means for successively storing information to I first or last display lines and successively shifting the following display lines to a blank space, and, displaying the display line preceding or following the already indicated display line on the last or first display line thus rendered blank.

1 Claim, 20 Drawing Figures MEMORY DATA WRIT- ING SIGNAL DIFFER ENTIATOR BUFFER IRCUIT AIDRESS COUNTER 1 e0 CIRCUIT PATENTEDnucze m2 SHEET 1 BF 5 3 41 HEAD MARK FIG.1

41 41 HEAD MARK I Ill Fl G.3

F I G.4A

ONE FIELD SCAN PERIOD FIG.4B

F|G.4C

PATENTEDmczs m2 SHIZU 3 [1F 5 Fl G.1OA

BUFFER REGISTER CHARACTER GENERATOR DECODER] 56 CRT. E

CRT.

B'UFFER PATENIEDMZ IM 3.688.299

SHEET S [if 5 FIG. 10B

MEMORY DELAY CIRCUIT DI FFER ENTIATOR DAM WRIT- ING SIGNAL BUFFER COINCIDENCE CIRCUIT ADDRESS COUNTER SUB.1 8O

CIRCUIT CONTROL DEVICE FOR DISPLAY APPARATUS CROSS-REFERENCE TO RELATED APPLICATION This application is a continuation-in-part of the U.S. patent application Ser. No. 724,439, filed on Apr. 26, 1968, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a control device for an information display apparatus and more particularly to a control device for a terminal display device such as a cathode ray tube utilized in an interlocked relation with an electronic computer.

Exchange of information between an electronic computer, for example, and an operator is effected by a perforator including a keyboard, and a cathode ray tube, the latter being utilized as a display apparatus together with a memory device. Thus, information to be displayed which is supplied from the computer is first stored in the memory device and then information corresponding to respective words to be displayed on the display surface or screen of the cathode ray tube is successively read out from the memory device by a display control circuit and is applied to a word generating circuit, for example, in which information is converted into corresponding pattern signals suitable to be displayed as words on the display surface of the cathode ray tube. Pattern signals thus obtained are applied to the cathode ray tube to successively display word patterns, word after word, on its display surface. Concurrently with the display of information from the electronic computer on the display surface, symbols, known as markers (or cursors) and representing the position on the display surface at which the next succeeding information is to be displayed, are also displayed. When information is displayed at a position of the marker on the indicating surface the marker is moved by one word. In this manner the marker is successively moved on the display surface in one direction, and when another piece of information is received upon completion of display of information included in one digit, the position of the marker is automatically shifted to the next line to display another piece of information at the first position thereof, thus displaying a predetermined piece of information on the display surface.

Where the amount of information sent to the cathode ray tube from the computer is equal to or less than the amount of information that can be displayed by the cathode ray tube the display of information may be fixed on the display surface thus providing an accurate indication of the displayed content. However, in case the amount of information received exceeds the capacity of the display surface, or when all positions of the display surface have been occupied, it is necessary to form a command information and supply it to the computer or memory device which issues a command to successively erase information displayed at the earlier stage to receive and display an additional amount of information or to supply just a sufficient amount of information to the cathode ray tube that can be displayed to provide a fixed display and which sends to the display apparatus succeeding information to be displayed. Further where information of the amount that exceeds the display capacity of the cathode ray tube is to be displayed with a system wherein display of information is not fixed on the display surface but additional information is successively displayed, as the content of the display varies regardless of the operator there is the disadvantage that the operator may overlook some important information that has been displayed. Further, in the case of fixed display as all pieces of information that have been displayed on the cathode ray tube are replaced at the same time by new information, the continuity of information before and after said replace-.

SUMMARY OF THE INVENTION The object of this invention is to provide an improved control device for an information display apparatus wherein at any time during the display operation, by merely operating a shifting key switch, information respectively preceding and succeeding the information that is just displayed on the display apparatus is readily displayed on the display surface with the same order as that of information initially sent from the computer. According to this invention there is provided a control device for a display apparatus designed to vary the contents of information to be presented on the display surface of at least one cathode ray tube, which comprises a memory device consisting of a magnetostrictive delay line; means for successively storing inputs from an input terminal of a cathode ray tube with a head mark, blocks of information consisting of a plurality of display lines to be indicated in the display surface of the cathode ray tube in succession to the head mark; first feedback means for feeding back stored information directly from the output terminal to the input terminal of the memory device; second feedback means for feeding back stored information from the output terminal to the input terminal of the memory device by delaying said information for a sufficient length of time to present one display line on the display surface of a terminal display apparatus; third feedback means for feeding back stored information directly to the input terminal of the memory device at a pointdisplaced from the output terminal toward the input terminal of said memory device for a sufficient distance to store information corresponding to one display line to be indicated on the display surface; means for visibly displaying on the cathode ray tube the information following the head mark already appearing at the output terminal of the memory device; backward and forward shifting keys corresponding to the cathode ray tube so as to generate signals for shifting the display of information backward and forward; means for detecting the head mark of the cathode ray tube upon the closure of the backward shifting key and rendering the first feedback means inoperable and the second feedback means operable according to the detected signal; means for drawing out from the computer, when the first feedback means is rendered inoperable, the information preceding that which is to be display in succession to the head mark already indicated on the display surface of the cathode ray tube and presenting the first mentioned information on said display surface, means for successively feeding back to the input terminal of the memory device through the second feedback means the information drawn out when the first feedback means was made inoperable; means for detecting the head mark of the cathode ray tube upon the closure of the forward shifting key and rendering the first feedback means inoperable' and the third feedback means operable according to the detected signal; and means for drawing out from the computer the information succeeding that which is to be indicated on the display surface of the cathode ray tube and displaying the first mentioned information on said display surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1, 2, 3, 5 and 7 illustrate information formats having the content stored in a memory device used in a control device according to an embodiment of this invention;

FIGS. 4A, 4B, 4C, 6A, 6B, 6C, 8A, 8B, and 8C show the wave forms of vertical scanning signals used in displaying the contents of FIGS. 3, 5 and 7 on a' terminal display apparatus or cathode ray tube;

FIG. 9 presents part of the letters included in one display line indicated on a cathode ray tube according to the invention;

FIGS. 10A and 10B are circuit diagrams of a display control device according to an embodiment of the invention;

FIG. 11 illustrates the operation of a memory device used in the display control device of FIG. 10B; and

FIGS. 12A and 12B indicate letters presented on the display surface of the cathode ray tube by way of illustrating the operation of the display control device of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be outlined with reference to FIGS. 1 through 9. As shown in FIG. 1 a memory device 41 is divided into a plurality of memory blocks 41 to 41 the contents stored in each block corresponding to one line of characters to be displayed on the displayed surface of a terminal display apparatus of a cathode ray tube. Under the control of a control circuit (not shown), information to be displayed on the respective face plate of the cathode ray tube together with information positioned at the leading end thereof and representing head marks inherent to respective terminal display apparatus is sequentially written in the memory blocks as shown in FIG. 1. For example, where three cathode ray tubes A, B and C (shown in FIG. 10) are used, information representing a head mark HA inherent to the cathode ray tube A is attached to the leading end of information corresponding to two lines, and this information of the head mark HA and the information corresponding to the first one of said two lines are written in the first memory block 41, whereas information corresponding to the second line in the second memory block 41 Then, when it is desired to write in the memory device 41 information of one line,

for example, to be displaced on the terminal display device B, information for the terminal display device A which is written in the first and second blocks 41 41 is transferred to the second and third blocks 41 and 41 respectively and the information of one line is written in the first block 41 together with the information of the head mark HE inherent to the terminal display device B and attached to the leading end of said information of one line, as shown in FIG. 2.

Further where it is desired to write in the memory device 41 information of two lines, for example, to be displayed on the terminal display apparatus C, as shown in FIG. 3, information that is stored in the memory device 41 is shifted to blocks spaced back by a number of blocks corresponding to two lines, that is information written in the first to third blocks, 41 to 41;, is transferred to the third to fifth blocks 41;, to 41 while at the same time information of the first line is written in the fist block 41 together with information of the head mark I-IC inherent to the terminal display apparatus C and attached to the leading end of the information of two lines to be displayed on the terminal display device C, while information of the second line is written in the second block. In this manner, information to be displayed on the respective terminal display apparatus is sequentially written in memory blocks 41 to 41,, of the memory device 41 together with head marks inherent to respective terminal display apparatus and attached to their leading ends. When a certain line of the information displayed on one of the terminal display apparatuses becomes unnecessary, information of that line is removed from a corresponding block and information stored in the memory block behind the block from which information is to be removed is sequentially transferred forward one block each to occupy the emptied block, thus leaving the last block unoccupied, as will be more fully described later.

Information stored in the memory device is repeatedly read out by sequentially scanning with the control circuit and the information read out is converted into pattern signals such as characters by means of a character generating device. Each time a head mark is detected it is applied to a corresponding terminal display device. Concurrently therewith its vertical scanning signal is generated to provide vertical scanning, and horizontal scanning is also provided to display read out information on the display surface. Utilization of a horizontal scanning signal common to all terminal display apparatuses enables to simultaneous display of different information sequentially on respective display surfaces starting from their upper end. Further, the interval of time required to read out information of one memory block is made equal to that required for scanning one line of the display surface of the terminal display apparatus. Detail of the vertical scanning is as follows: At the instant z a when the head mark HC for the terminal display apparatus C is detected, a vertical scanning signal as shown in FIG. 4A is generated for the terminal display apparatus C to begin its vertical scanning whereby to display information that has been stored in the first and second memory blocks 41, and 41 of the memory device 41 shown in FIG. 3 on the first and second lines from the top of the display surface of the terminal display apparatus C. When the head mark l-IB of the terminal display device B is detected at the instant z 2 later than the instant t o by an interval during which information of two lines can be read out from the memory device 41, a vertical scanning signal as shown in H6. 48 is generated to begin the vertical scanning of the terminal display apparatus B thereby displaying information stored in the third memory block 41 of the memory device 41 on the first line from the top of the display surface of the terminal display device B. Likewise upon detection of a head mark HA of the terminal display apparatus A at the instant t 3 later than the instant t 2 by an interval during which information corresponding to one line can be read out from memory device 41, a vertical scanning signal as shown in FIG. 4C is generated to begin the vertical scanning of the terminal display apparatus A thereby displaying information that has been stored in the fourth and fifth memory blocks l l and 41 of the memory device ll on the first and second lines from the top of the display surface of the terminal display apparatus A. in this manner, each time a head mark is detected the vertical scanning of the corresponding terminal display apparatus is initiated to display information. Where information to be displayed on the terminal display apparatus C is increased to three lines, as shown in MG. 5, information to be stored on terminal display apparatuses A and B is respectively shifted one block backward, thus storing them in the fourth and following memory blocks whereby information to be displayed on the third line of the terminal display apparatus C and stored in the third memory block 4-1 in this case, vertical scanning of respective terminal display apparatus is performed in the following manner. With regard to the terminal display apparatus C, a vertical scanning signal as shown in FIG. 6A is generated at instant t when its head mark HC is detected to begin vertical scanning and when the head mark E5 of the terminal display apparatus B is detected at the instant later than t by an interval during which information corresponding to three lines can be read out of the memory device 41 a vertical scanning signal as shown in FIG. 6B is generated to begin its vertical scanning. Similarly when the head mark HA of the terminal display apparatus A is detected at the instant later than by an interval during which information corresponding to one line can be read out from the memory device ll a vertical scanning signal signal as shown in HG. 6C is generated to begin its vertical scanning. By comparing FIG. 6 with FIG. 4, it can be noted that in the condition shown in FIG. 4 the vertical scanning signal for the terminal display apparatus B begins at the instant t but owing to the increase of one line in the display apparatus C the vertical scanning signal for the terminal display device B will begin at the instant later than t by an interval corresponding to one line. Thus, under this transient condition the vertical scanning signal is delayed for an interval corresponding to one line.

Also in the terminal display device A owing to the increase of one line in the terminal display apparatus C, the vertical scanning signal is delayed one line during the transient condition.

Regardless of the shift of the vertical scanning signal, it is possible to assure displayed information free from the effect of such shift, as the vertical scanning signal of an ordinary television receiver can follow such shift. Thus, each time a. head mark is detected the vertical scanning operation of a corresponding terminal display apparatus is initiated to display information. When information corresponding to one line is eliminated from information to be displayed on two lines of the terminal display apparatus C, information to be displayed on terminal display apparatuses A and B is shifted one block forward thus storing them in the second and following memory blocks as shown in FIG. 7. In this case the vertical scanning operation of respective terminal display apparatuses is performed in the following manner. The terminal display apparatus C generates a vertical scanning signal as shown in FIG. 8A at the instant t when the head mark l-lC is detected by the control device thereof. Whereas the terminal display apparatus B generates a vertical scanning signal as shown in H6. 813 at the instant t when its head mark HE is detected. The instant I, is later than t by an interval during which information corresponding to one line can be read out from the memory device ill. Likewise the terminal display apparatus A generates a vertical scanning signal as shown in H6. 8C when its head mark NC is detected at the instant t later than t, by an interval of reading out information corresponding to one line. in this case also, the vertical scanning signal of the terminal display apparatus B which begins at under the condition shown in FIG. 4 has changed to begin at the instant t, which is earlier than by the time instant to read out one line.

Thus, under transient state the vertical scanning signal for the terminal display apparatus B is advanced one line. Similarly, under the transient state the vertical scanning signal for the terminal display apparatus A is also advanced one line. Thus, each time a head mark is detected the vertical scanning operation of the corresponding terminal display apparatus is commenced to display information thereon. During these procedures, increase or elimination of information to be displayed on respective terminal display apparatuses can be treated according to their sequence of arrival so that information can be shifted forward or backward by a maximum of one block in the memory device during the scanning time required to scan one display surface of a terminal display apparatus. Since with an ordinary television receiver the vertical scanning signal thereof can follow such shift there is no effect upon display information.

FIG. 9 shows a letter A included in a piece of information corresponding to one display line presented on the display surface of a terminal display apparatus or cathode ray tube according to this invention. The information of one display line is, as described above, equal to the amount of information stored in one memory block included in the memory device ll. Said information is designed, as shown in MG. 9, to be displayed by eight horizontal scanning lines 44 per display line. As later described, the information stored in one memory block included in the memory device All is supplied to the known character generator to be converted to television signals presented on the display surface by, for example, eight scanning lines, thereby indicating under control of the character generator the aforesaid letter A consisting of a plurality of bright spots 43 on a prescribed cathode ray tube.

- There will now be described by reference to FIGS. 19A and MB an embodiment of this-invention. The memory device 4i consists of magnetostrictive delay line or lines 31 (FIG. 1013) which have successively stored therein the information of letters representing the head marks HA to HR of the cathode ray tubes A to H from the computer 45 through the buffer register 47 and AND gate 49. This write-in in the magnetostrictive delay lines 31 is effected by conducting thereto a piece of letter information from the buffer register 47 only when the AND gate 49 is supplied with data-writing signals from the computer 45 and signals from the coincidence circuit 28.

Since the memory'device 41 (of FIG. 1) consists in practice of a magnetostrictive delay line 31 information is collected for each display line to be indicated on the display surface and successively conducted to said delay line. Then there will be formed therein a plurality of memory blocks (shown theoretically in FIGS. 1, 2, 3, and 7) each stored with a piece of information representing one display line. FIG. 11 shows 33 storage blocks 1 l, to 11 formed in the magnetostrictive delay line. These storage blocks used in practice correspond to the theoretical memory blocks of FIG. 1. The input terminal of the magnetostrictive delay line or lines is fitted with a transducer and write-in amplifier and the output terminal thereof with a transducer and read-out amplifier. Since, however, this is a know technique, the description thereof is omitted. The delay lines have a predetermined delay characteristic. In this embodiment, the magnetostrictive delay lines 31 are shown as divided into 33 storage blocks 11,, 11 11 each block having a length sufficient to delay for a predetermined time information corresponding to one line of the display surface of the cathode ray tube, which are sent from the computer via a reception control circuit. Accordingly, by continuously applying successive information from the computer to the magnetostrictive delay lines 31, each storage block will store the information corresponding to one of the respective lines on the display surface and the information is successively transmitted through the magnetostrictive delay lines. Ordinarily the information supplied from the computer is in the form of binary digital signals and the information of each unit is comprised by a digital signal of several bits, so that a plurality of magnetostrictive delay lines having substantially the same delay characteristic 7 are used in parallel corresponding in number to the number of bits of the information supplied. In this ex ample, it is assumed that the number of bits is four.

The circulation of the information stored in the magnetostrictive delay lines 31 is effected by applying the output from an AND gate circuit 50 to a reset terminal of a flip-flop circuit 51 to reset the same thus applying the output from the negative terminal to an AND gate circuit 32. Three inputs to the AND gate circuit 50 are the pulse from a clock pulse generator 37, the output from the positive terminal of a flip-flop circuit 52 or 53 and the output signal from an OR gate circuit 54. The OR gate circuit 54 is arranged to receive an output corresponding to the logical product of the memory information from the magnetostrictive delay lines 31 supplied through a buffer register 56 to seven two-input AND gate circuits 55 and outputs supplied from seven head mark signal generating circuits corresponding to the stored information and representing the head mark. In this case, the presence of the output from the flipflop circuit 52 or 53 shows that the forward or backward shifting key is depressed to close switch 14F or 1413, but under this state there is no input to the set terminal of the flip-flop circuit 51 or the output from the AND gate circuit 58. In other words, the output from an AND gate circuit 59 is not applied to one of three input terminals of the AND gate circuit 58. The circuit shown in FIGS. 4, 10A and 10B is constructed such that among the information stored in the magnetostrictive delay lines 31, that represented by the head mark A, for example, the information which is being displayed on the display surface of a cathode ray tube A among eight cathode ray tubes A, B, H comprising the terminal display apparatus can be shifted in the forward or backward direction. Accordingly where the logical product between the information supplied to the AND gate 59 from the magnetostrictive delay lines 31 through the buffer register 56 and the encoded signal from a circuit 57A that generates the head mark A can not be obtained, that is when said information does not correspond to the head mark A the AND gate 58 will not provide any output so that the circulation of the information through magnetostrictive delay lines 31 is performed normally.

While information to be displayed is circulated through the main memory device via the AND gate 32, said information is supplied to the character generator 30 through a subcirculating delay memory 33 consisting of a delay circuit. The character generator 30 successively converts pieces of information received to character signals corresponding to the cathode ray tubes A to H, and conducts said signals to one input terminal of the AND gates 40A to 40H respectively. This character generator 30 may preferably consist of the type disclosed in the US. Pat. No. 3,426,344. The circulating information is conducted through the buffer register 56 to the decoder 42, which decodes the head mark signal of the information supplied from the memory device 31 so as to select the corresponding one of the cathode ray tubes A to H. Output from the decoder 42 opens that of the AND gates 40A to Mill which was designated by the detected head mark. Thus the character signal from the character generator 30 is also designated and displayed on that of the cathode ray tubes A to H which corresponds to said character signal.

When a signal corresponding to the head mark A is applied to the AND gate circuit 59 from the magnetostrictive delay lines 31 via the buffer register 56 during the interval wherein the backward shifting key, for example, is depressed to close the switch 148 to provide an output from the positive terminal of the flipflop circuit 53 a signal will be applied to the set terminal of the flip-flop circuit 51 in response to a clock pulse whereby the output from the negative terminal of the flip-flop circuit 51 disappears whereas an output is provided on the positive terminal which is applied to one input terminal of the three-input AND gate circuit 34B. When the first information which follows the head mark A" and is being displayed on the first line from uppermost portion of the screen of the cathode ray tube A is transferred from the first storage block 11 to the last storage block 11 the AND gate 32 is enabled to empty the memory block 11 whereby the first line of the screen of the cathode ray tube A is cleared and at the same time the information that had been blocked by the AND gate 32 is now applied to the delay circuit 33. Then the transfer of the second information to be displayed on the second line of the same screen from block 11 to block 11 is blocked by the action of AND gate 32 while at the same time the AND gate 348 is enabled to apply the first information to block 11 from the delay circuit 33 through AND gate 61 and OR gate 63. inasmuch as one input terminal of two-input AND gate 61 is connected to the negative terminal of the flip-flop circuit 64 the backward shifting operation would not be efiected unless an input is applied to the reset terminal of the flip-flop circuit 64. Thus, an output provided by an AND circuit Thus, an output 67 in the form of a logical product between a signal supplied by the AND gate 34B via an OR gate circuit 65 and a buffer register 66 and an output provided by an AND gate circuit 68 as the logical product among three signals from the flip-flop circuit 53 and the clock pulse generator 37 are applied to the reset input terminal of the flip-flop circuit 64 via an OR gate circuit 69.

Where the forward shifting switch MP is operated a similar operation is performed by the output from the AND gate 348.

The above described forward or backward shifting operation is performed only when an input is applied to the reset terminal of the flip-flop circuit 64 and there is no output from its negative terminal. In other words, there are two cases, viz. one the case wherein an output is provided by an AND gate 70 and the other wherein an output is provided by an AND gate 71.

Outputs from flip-flop circuit 52, clock pulse generator 37 and Or gate 72 are applied to the AND gate 70. Seven AND gate circuits 73 connected to the OR gate 72 operate to obtain the logical products between the I output from a buffer register 66 and the output from circuits 578 to 57H for generating head mark signals B through H and the output from the negative terminal of the flip-flop circuit 64 will be interrupted when the forward key 14F is depressed and the output from the buffer register 66 corresponds to head marks 13 through H.

AND gate 71 is connected to receive outputs from the flip-flop circuit 53, clock pulse generator 37 and AND gate 59. Consequently, when the backward key 148 is depressed and when an information corresponding to the head mark A is applied to the AND gate 59 through bufier register 56 the negative terminal output of the flip-flop circuit 64 will be interrupted.

The backward operation is described by referring to FR]. 11. The first storage block 11 is connected to the last block 11 via the serially connected delay circuit 33 and a delay control AND gate circuit 34B. The delay time provided by the delay circuit 33 is set equal to the time interval required for an information in the memory device 11 to move one memory block. Thus, upon application of the keying signal from flip-flop circuit 52 to AND gate 348, information that has been displayed on the screen of the cathode ray tube will be shifted one line in the direction opposite to the order of information sent from the computer 45 via AND gate 49 or towards lower side of the screen. Thus, when the second line of the same screen is transferred to the last block 11 from the first block 11, the memory control circuit of this embodiment operates to close the circulating gate circuit 32 to prevent the second information from being transferred to the last block 11 Concurrently therewith the AND gate 348 is opened to pass the first information which was previously applied to the delay circuit 32 to write it in the last block 11 As a result the infonnation B which has been displayed on the first line of the screen as shown in FIG. 12B will be displayed on the second line as shown in FIG. 12A. Similarly information that has been displayed on the second succeeding lines is transferred to the third and following lines, respectively. Thus the information that has been displayed on the display surface of a cirtain cathode ray tube is transferred'backwardly and the first line thereof is blanked.

The first display line rendered blank, that is, the last block 11 is supplied from the computer 45 with a piece of information to be displayed immediately prior to that which is indicated on the second display line. There will now be described this operation. The forward operation is described by referring to FlG. l 1.

An AND gate circuit 34F is connected between the second block 11 and the last block 11 of the memory device 11, whereby upon application of the keying signal generated by depressing the forward operation switch 14F, when the first information displayed on the first upper line of the screen of the cathode ray tube is transferred from the first block 11 to the final block 11 the AND gate circuit 32 is closed by setting flipflop 51 to interrupt the first information while at the same time the AND circuit 34F is opened to transfer the second information, moving from the ninth block 11 to the eighth block 11 to the last block 11 Consequently, the first information is erased from the first line and replaced by the second information on a cirtain cathode ray tube surface. In the same manner, information displayed on the third and following lines is transferred respectively to the second and following lines, thus clearing the last line.

Since flip-flop circuits 52 and 53 are reset respectively by a signal obtained by passing the output from the positive terminal of the flip-flop circuit 51 through a built down differentiating circuit 74, in order to provide continuous forward or backward shifting operation it is required that the forward or backward shifting key 14F or 148 should be continually depressed.

During the forward shifting operation, the output from the AND circuit 58 is also applied to the set terminal of the flip-flop circuit to apply to AND circuit 76 the output from the positive terminal whereby AND gate circuit 76 takes an AND operation of three outputs from the flip-flop circuit 52 and from the AND circuit 50 to supply a signal from the OR gate circuit 78 to the marker register 18.

Similarly during the backward shifting operation, the AND circuit '77 takes an AND operation of two output signals from AND circuit 58 and flip-flop circuit 52 to send a signal to marker register 18 via OR gate 78.

When the forward 'or backward shifting key 14F or 14B is depressed, the marker register 18 receives the content in an address counter 79 as the backward address and forward address, respectively, and these address signals are stored in said register 18 when the signals from OR gate 78 are applied to the set terminal thereof. I

During the forward shifting operation, where the information taken out from the memory device 31 by the AND circuit 59 is detected to correspond to the head mark A if the AND circuit 50 detects that the information has changed to other head mark than A," the AND circuit 76 provides an output to set marker register 18. However, at this time, since the information has already been transferred from the display apparatus A to another display apparatus the forward address is present to an address higher than one line so that in order to restore it to the original address a subtractionone circuit 80 is used.

In this embodiment, the carry signal from the address counter 79 is utilized as the transmission request signal to transmit information from computer 45 to the memory device 31 via a buffer register 47 and AND gate 49.

The embodiment of FIGS. A and 10B is so designed as to advance or retract the information presented on the display surface of the cathode ray tube A by one display line each time. Application of this arrangement to the other cathode ray tubes permits the same advancing or retracting operation thereon.

As described hereinabove, according to the embodiment, by the depression of the backward shifting key 143, the displayed information is shifted to erase the last one line E while at the same time to display the information A of one line preceding the first line B as shown in FIGS. 12A, 123. Moreover, by the selective operation of the backward shifting key, such operation may be performed either continuously or intermittently, with the result that even when a particular information is overlooked, it can be seen again by shifting the information in the backward direction thus assuring correct and accurate reading of the information. Moreover, in addition to the backward shifting, the information is displayed according to the same sequence as in the computer, reading thereof is greatly facilitated. Further manipulation of the apparatus is very simple because information can be shifted backwardly by merely depressing the backward shifting key 1413.

Upon depression of the forward shifting key 14F, information being displayed is shifted to erase the first line A and to display succeeding information E on the last line as shown in FIG. 128. Thus the continuation of information could be readily understood, thereby eliminating such defect as relying upon the memory of the operator where all information on the display surface is renewed. Further the operation to shift the displayed information to erase the first line and to display the next succeeding information on the last line can be effected either continuously or intermittentiy by the adjustable operation of the forward shifting key 14F.

Cons e uently, there is no dan er of overlooking the requisi e displayed information us assuring re y and accurate reading of the information.

What we claim is:

l. A control device for display apparatus designed to vary the contents of information to be presented on the display surface of at least one cathode ray tube, which comprises a memory device consisting of a magnetostrictive delay line; means for successively storing from the input terminal with the head mark of a cathode ray tube, a block of information consisting of a plurality of display lines to be indicated on the display surface of the cathode ray tube in succession to the head mark;

first feedback means for feeding back stored information directly from the output terminal to the input terminal of the memory device; second feedback means for feeding back stored information from the output terminal to the input terminal of the memory device by delaying said information for a sufficient length of time to present one display line on the display surface of a terminal display apparatus; third feedback means for feeding back stored information directly to the input terminal of the memory device at a point displaced from the output terminal toward the input terminal of said memory device for a sufficient interval to store information corresponding to one display line to be indicated on the display surface; means for visibly displaying on the cathode ray tube the information following the head mark already appearing at the output terminal of the memory device; backward and forward shifting keys corresponding to the cathode ray tube so as to generate signals for shifting the display of information backward and forward; means for detecting the head mark of the cathode ray tube upon the closure of the backward shifting key and rendering the first feedback means inoperable and the second feedback means operable according to the detected signal; means for drawing out from the computer, when the first feedback means is rendered inoperable, the information preceding that which is to be displayed in succession to the head mark already indicated on the display surface of the cathode ray tube and presenting the first mentioned information on said display surface; means for successively feeding back to the input terminal of the memory device through the second feedback means the information following the head mark in succession to the information drawn out when the first feedback means was made inoperable; means for detecting the head mark of the cathode ray tube upon the closure of' the forward shifting key and rendering the first feedback means inoperable and the third feedback means operable according to the detected signal; and means for drawing out from the computer the information succeeding that which is to be indicated on the display surface of the cathode ray tube and displaying the first mentioned information on said display surface. 

1. A control device for display apparatus designed to vary the contents of information to be presented on the display surface of at least one cathode ray tube, which comprIses a memory device consisting of a magnetostrictive delay line; means for successively storing from the input terminal with the head mark of a cathode ray tube, a block of information consisting of a plurality of display lines to be indicated on the display surface of the cathode ray tube in succession to the head mark; first feedback means for feeding back stored information directly from the output terminal to the input terminal of the memory device; second feedback means for feeding back stored information from the output terminal to the input terminal of the memory device by delaying said information for a sufficient length of time to present one display line on the display surface of a terminal display apparatus; third feedback means for feeding back stored information directly to the input terminal of the memory device at a point displaced from the output terminal toward the input terminal of said memory device for a sufficient interval to store information corresponding to one display line to be indicated on the display surface; means for visibly displaying on the cathode ray tube the information following the head mark already appearing at the output terminal of the memory device; backward and forward shifting keys corresponding to the cathode ray tube so as to generate signals for shifting the display of information backward and forward; means for detecting the head mark of the cathode ray tube upon the closure of the backward shifting key and rendering the first feedback means inoperable and the second feedback means operable according to the detected signal; means for drawing out from the computer, when the first feedback means is rendered inoperable, the information preceding that which is to be displayed in succession to the head mark already indicated on the display surface of the cathode ray tube and presenting the first mentioned information on said display surface; means for successively feeding back to the input terminal of the memory device through the second feedback means the information following the head mark in succession to the information drawn out when the first feedback means was made inoperable; means for detecting the head mark of the cathode ray tube upon the closure of the forward shifting key and rendering the first feedback means inoperable and the third feedback means operable according to the detected signal; and means for drawing out from the computer the information succeeding that which is to be indicated on the display surface of the cathode ray tube and displaying the first mentioned information on said display surface. 